Tratamento eletroquímico de uma amostra real de água produzida utilizando o ânodo de Ti/IrO2-Ta2O5 mediada pela produção de espécies de cloro ativo

Abstract

When oil is extracted from different production zones (onshore or offshore), an aqueous residue called oilfield wastewater or produced water (AP) is produced together, which represents the largest amount of waste from crude oil production. Produced water contains various organic and inorganic components, for example, formation salts, dissolved gases, suspended solids, organic compounds from contact with oil, residual chemical compounds from well operations, microorganisms, in addition to the possible presence of heavy metals and components with some type of radiation and its discharge may pollute surface, groundwater and soil. Both the disposal of this effluent and its reuse for reinjection in production wells, a previous treatment is necessary, once that due to its chemical composition, it can somehow favor corrosive damage to pipes, etc. One of the most used processes for the treatment of this type of effluent has been the advanced oxidative electrochemical processes. For this purpose, in the present work, the effect of the Ti/IrO2-Ta2O5 anode on the removal of the organic matter from a sample of produced water from the oil industry was evaluated and the effect of active chlorine species on the disinfection of this effluent was also evaluated. Thus, according to the results obtained, the influence of the anodic material allowed a significant decrease in the chemical oxygen demand, 79%, 73,5% and 76,9% with energy consumption of 48,77; 129,54; 244,60 kWh dm-3 when applied 30, 60, 90 mA cm-2 of current density, respectively. The material showed electrocatalytic properties for obtaining active chlorine species and their best disinfection effects by the indirect mechanism when applying current densities 30 and 90 mA cm-2.